PHYSIOLOGICAL-RESPONSES OF PLANTS TO SALINITY - A REVIEW

Root-zone salinization presents a challenge to plant productivity that is effectively countered by salt-tolerant halophytic plants, but unfo rtunately, much less successfully by major crop plants. The way in whi ch salt affects plant metabolism is reviewed. Cellular events triggere d by salinity, namely salt compartmentation, osmotic adjustment and ce ll wall hardening are connected to the whole plant responses, namely l eaf necrosis, altered phenology and ultimately plant death. The roles of ion exclusion and K/Na discrimination in mediating crop response to salt appear to be central to the tolerance response, but they are by no means essential. The processes involved in regulating ion uptake at the membrane level are considered. Recent work elucidating the intera ction between calcium and salinity tolerance is reviewed.